docs: def is_cdl(filename):
      '''
      Quick check for .cdl ascii file
  
      Example:
          netcdf sample_file {
          dimensions:
              name_strlen = 7 ;
              time = 96 ;
          variables:
              float lat ;
                  lat:units = "degrees_north" ;
                  lat:standard_name = "latitude" ;
                  lat:long_name = "station latitude" ;
          etc...
  
      :param str filename: Absolute path of file to check
      :param str data: First chuck of data from file to check
      '''
      if os.path.splitext(filename)[-1] != '.cdl':
          return False
  
      with open(filename, 'rb') as f:
          data = f.read(32)
      if data.startswith(b'netcdf') or b'dimensions' in data:
          return True
      return False